The water-telescope is an instrument which the people of Norway have found of so great utility, that there is scarcely a single fishing-boat without one of three or four feet in length, which they carry in their boats with them when they go a-fishing. When they reach the fishing-grounds, they immerse one end of this telescope in the water, and look through the glass, which shews objects some ten or fifteen fathoms deep as distinctly as if they were within a foot of the surface. When a shoal of fish comes into their bays, the Norwegians instantly prepare their nets, man their boats, and go out in pursuit. The first process is minutely to survey the ground with their glasses, and where they find the fish swarming about in great numbers, they give the signal, and surround the fish with their large draught-nets, and often catch them in hundreds at a time. Without these telescopes their business would often prove precarious and unprofitable; as the fish, by these glasses, are as distinctly seen in the deep, clear sea of Norway, as gold-fish in a crystal jar. This instrument is not only used by the fishermen, but is also found aboard the navy and coasting-vessels of Norway. When their anchors get into foul ground, or their cables warped on a roadstead, they immediately apply the glass, and, guided by it, take steps to put all to rights, which they could not do so well without the aid of the rude and simple instrument, which the meanest fisherman can make up with his own hands, without the aid of a craftsman. This instrument has been lately adopted by the Scotch fishermen on the Tay, and, by its assistance, they have been enabled to discover stones, holes, and uneven ground, over which their nets travel, and have found the telescope answer to admiration, the minutest object in twelve feet of water being as clearly seen as on the surface. We see no reason why it could not be used with advantage in the rivers and bays of the United States. _Experimental Investigations to Discover the Cause of the Change which takes place in the Standard Points of Thermometers._ By JOHN ADIE, F.R.S.E., F.R.S.S.A. Communicated by the Author.